I don’t. I don’t make laws.

Neither does the ADL for that matter.

But generally, it’s understood that

Antisemitism is hostility to, prejudice towards, or discrimination against Jews.

Criticism of the Israeli government is not antisemitism. The Israeli government is not a race anymore than Hamas is.

However… if you need a specific “line” because you’re an asshole, in the us, the “legal line”… is pretty easy to find. the FBI defines a hate crime as:

The UCR Program defines hate crime as a committed criminal offense which is motivated, in whole or in part, by the offender’s bias(es) against a:

race religion disability sexual orientation ethnicity gender gender identity

Seems pretty easy to say “don’t commit hate crimes against Jews”, right? Or, any one else for that matter.

Nazis are not a race either. They are generally the ones pushing hate crimes, though, and yes, I can have me feeling that punching a Nazis is a good thing while recognizing it’s also assault.

As for whose a Nazi… when they admit to it, or do and say things that are blatantly Nazi-things. Interesting, that Einstein and other jews called Herut (political party that came from the Irgun paramilitary group during the Palestine Mandate) a bunch of Nazis. (This is why I added the antisemitism stuff and hate crime stuff at the start.)